1. Field of the Invention
The invention relates to a voltage sensor for monitoring electronic ignition circuits, in particular to a voltage sensor which can be connected separately to the ignition line and communicates via the same.
2. Description of the Related Art
Electronic ignition circuits consist of several electronic igniters connected to a generally bi-polar ignition line in turn connected to an ignition device or programming device. The igniters are initiated by a voltage or pulse sequence supplied by the ignition device in the ignition line. A capacitor located in the igniter is charged and the delay time programmed in. Once initiation has finished the igniter draws its operating energy from the capacitor. Therefore, the capacitor voltage during initiation has to be set such that there is sufficient energy available during the course of the programmed delay time, in other words at the ignition point, for the ignition means of the igniter to ignite reliably.
However, in electronic ignition systems wired in parallel the power consumption of the igniter, like parasitic leakage currents, leads to voltage drops on the ignition lines owing to insulation damage or incorrect wiring. There is therefore no guarantee that igniters located further away from the ignition device will receive a programming signal whose voltage is high enough to charge completely the capacitor. However, this is imperative for orderly operation.
The possibility of measuring the ignition circuit electrically before starting programming is known. However, this method is very complex and time intensive.
Also in existence are igniters with integrated voltage sensors for measuring the voltage on the ignition line at each individual igniter. However, this has the critical drawback that the construction of each individual igniter is complicated and this increases the costs and susceptibility to faults. In addition, the power consumption increases and thus also the voltage drop on the ignition line.